I wanted to expand on this. If I wasn't inclined or able to work on my instruments, what would I choose?Once I learned to touch up frets and neck finishes, I stopped thinking about upgrades. I can take a 100, 200, 400 dollar instrument and get it to a place where I like it as much as any MIA. (Assuming the neck is straight and takes a setup well.)
And sometimes they're already fantastic right off the rack!
Another important point is specs and preferences. I'll take an Affinity over a Cv 9 times out of 10, as I just prefer her satin finish and the slightly slimmer profile.
There's the law of diminishing returns. As you climb the ladder (eg Affinity, CV, Player, AM pro) the instruments about double in price. But do they double in quality? IMHO/IME, No. I'd say it's like a 10-30% increase in quality. but these little details are what each individual player must decide on, if it's worth the price to them. I'd say the diminishing returns cap out at about the Squier CV/Paranormal/Anniversary tier. But as the thread attests, gems are found in the lower tiers. I've picked up several Affinities I'd gig as-is.
I say lay your hands on as many basses as you can and see for yourself. Try non-Fenders too. Plenty of great P-style basses out there. Ibanez and Yamaha (to name a few) make some great ones that many would argue are better bang for the buck choices than the similarly priced Fender counterparts.
If your favorite is an "affordable" (for you) instrument- great! If you fall in love with the MIA, nothing wrong with that either. You'll know what to save up towards. Image and pride are import parts of the selection too; if you make yourself settle, you'll always be wanting that MIA in the end.
Good luck!